As the authorities searching for missing Malaysia Airlines flight MH370 race to investigate a series of potential black box 'pings' in the Indian Ocean, a senior official has reportedly claimed that the plane was "steered" around Indonesian airspace.

A senior Malaysian government source reportedly said the Boeing 777 curved north of Indonesia after it dropped of Malaysian military radar, according to further analysis of tracking data from neighbouring countries.

It apparently avoided Indonesia and its airspace altogether before turning again towards the southern Indian Ocean. The source told CNN such a route may have been taken intentionally in order to avoid radar detection.

Meanwhile, the man responsible for leading the search in Australia said that sounds detected from deep within the Indian Ocean represent an "important and encouraging lead".

Three separate signals have now been detected by ships hunting for the wreckage of the Boeing 777, two of which came from within just 2 km (1.25 miles) of each other.

The Royal Navy's HMS Echo, which carries sophisticated equipment for detecting underwater signals, was tasked with heading to the investigate the small patch of the search zone.

On Sunday, an Australian ship also equipped with a so-called "pinger locator" received a third signal in a different part of the search area around 300 nautical miles (555 km) away.

The earlier signals were reported by a Chinese patrol vessel as being at the same frequency emitted by flight data recorders aboard missing planes - 37.5 kilohertz.

"This is an important and encouraging lead, but one which I urge you to treat carefully," retired Australian Air Chief Marshall Angus Houston told reporters in Perth.

He stressed the signals had not been verified as linked to Malaysia Airlines Flight 370, which was travelling from Kuala Lumpur to Beijing when it disappeared on 8 March with 239 people on board.

"We have an acoustic event. The job now is to determine the significance of that event. It does not confirm or deny the presence of the aircraft locator on the bottom of the ocean," Houston said, referring to each of the three transmissions.

Houston confirmed that the Chinese ship Haixun 01 detected a signal again on Saturday within 2 km (1.4 miles) of the original signal, for 90 seconds. He said that China also reported seeing white objects floating in the sea in the area. He added that HMS Echo was expected to arrive in the area within the next two days.

The Australian navy's Ocean Shield, which is carrying high-tech sound detectors from the US Navy, will also head there, but would first investigate the sound it picked up in its current region.

Retired Air Chief Marshal Angus Houston (right) addresses the media in Perth
He said Australian air force assets were also being deployed on Sunday into the Haixun 01's area to try to confirm or discount the signals relevance to the search.

After weeks of fruitless looking, the multinational search team is racing against time to find the sound-emitting beacons and cockpit voice recorders that could help unravel the mystery of the plane. The beacons in the black boxes emit "pings" so they can be more easily found, but the batteries only last for about a month.

Investigators believe Flight 370 veered way off course and came down somewhere in the southern Indian Ocean, though they have not been able to explain why it did so.

The US Navy's towed pinger locator (TPL-25) sits on the deck of the Australian Defence Vessel Ocean Shield
The Chinese crew reportedly picked up the signals using a hand-held sonar device called a hydrophone dangled over the side of a small runabout — something experts said was technically possible but extremely unlikely.

The equipment aboard the Ocean Shield and the HMS Echo are dragged slowly behind each ship over long distances and are considered far more sophisticated than those the Chinese crew was using.

The Chinese Maritime Safety Administration (MSA) ship MV Xaixun 01 during a visit to Australia in 2013. Crew members reported hearing signals from within the search area on Friday and Saturday

Footage aired on China's state-run CCTV showed crew members in the small boat with a device shaped like a large soup can attached to a pole. It was hooked up by cords to electronic equipment in a padded suitcase as they poked the device into the water.

"If the Chinese have discovered this, they have found a new way of finding a needle in a haystack," said aviation expert Geoffrey Thomas, editor-in-chief of AirlineRatings.com. "Because this is amazing. And if it proves to be correct, it's an extraordinarily lucky break."